Dental flask



1.1. MOUNT.

DENTAL FLASK.

APPLlcATIoN man SEPTA 29, 1921,

1,4147,938 Patented May 3), w22,

rarer carica.

JAMES .5'. MOUN'LF CHICAGO, LLINES.

DENTAL FLASK.

To all fw hom it may conc-em Be it known that I, JAMES J. MOUNT, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Dental Flasks, of which the following isa specification.

This invention relates to centrifugal casting machines designed for casting dental inlays and the like.

The main objectsl of this invention are to provide a centrifugal casting machine having an improved form of flask, .1n which the Crucible and matrix may be simultaneously formed in a single mold; to provide improved means for moldingl the cruc1ble and matrix; to provide an limproved arrangement of the flask with respect to the rotatable supporting member; and tol provide improved mechanism for imparting a uniform rotation to the supporting member and flask.

An illustrative embodiment of this invention is shown'in the accompanying drawings. in which- Figure 1 is a side elevation of the apparatus, showing the upright 'support in vertical section.

Figure 2 is a side elevation of the apparatus taken from the right of Figure 1.

Figure 3 is a vertical section of the flask.

Figure 4 is a transverse section of the flask taken on the line 4-4 of Figure 3.

In centrifugal casting machines which are now in commonuse, the mold in which the matrix is formed is detachable from the Crucible. The crucible is made of suitable refractory material and is used for an indefinite number of operations, while the matrix mold is necessarily changed for each casting. When the same crucible is used repeatedly it becomes coated with slag` and other foreign substances which mixl withvthe molten metal flowing into the matrix to 'form an imperfect casting. heating of the same Crucible produces al rough surface Within the Crucible which greatly retards the flow of the molten metal.

The present invention involves the use of a flask in which the Crucible and matrix are simultaneously formed in a single mold and a new mold is made for each casting. The flask is carried by a rotatable supporting arm which is rotated by* an improved 4form of i Specification of Letters atent.

Also, the repeated.

Patented Nia.A 3), 1922.

.Application led September 29,1921. Serial No. 504,171.

driving mechanism constructed to operate un1formly for each casting operation.

In the form shown, the apparatus comprises an upright support 1, on which isl .other support. Mounted on the upright support is a laterally extending bracket 8, having a clampingpart 9 which embraces the tubular standard. Journaled in the bracket,

is a horizontally disposed shaft 10 having fixed on its outer end the rotatable member 3.

Loosely supported on the inner end of the shaft 10 is a gear 11, which projects through an opening 12 in the standard 5 for engagement with the driving mechanism. A pawl 13 is carried by the gear 11 and is held by aspring 14 in engagement with a ratchet 15 fixed on the inner end of the shaft 10. The pawl is arranged to drive the ratchet and shaft through the rotation of the gear 11 in one direction. Formed on the ratchet 15. is a hub 16 having a slot or recess 17 adapted to receive a catch 18, for locking the shaftV 10 against rotation. The catch 18 is in the form of a lever pivotall)vv mountedon the clampingr part 9 of the bracket.

The driving mechanism is in the form of a har 19. vertically slidable in the tubular standard 5, and having a rack 2() arranged t'o coact with the gear 11. Secured to the upper end of the rack bar, is a rod 21 whioh extends through an aperture in the threaded cap 6. Bearing.,r between the cap 6 and-a disk 22 secured to the upper end of the bar 19, is a compression spring` 23, which normally urges the rack bar to its lowermost position. A handle in the form of a head 24 is secured to the upper end of the rod 21 for raising the rack to its retracted position against the action of the spring 23.

The rotatable member 3 comprises a rod 2 5 having a hub 26 which is detachably secured to the shaft 10 by a tapered pin connection (not shown). Carried on one end of the rod, is an' adjustable counter-weight'y 28 for balancing the weight of the flask 4, `which is detachably secured at the other end of the supporting rod.` v The position of' the counter-weight on the rod may be adjusted by a thumb screw 29 which is threaded to the rod. The part of the rod which supports the` flask v4`i`s bent at an angle whichy will permit the molten metal to flow into the matrix lunder the action of inertia as well ascemtrifugal force, as hereinafter described. The flask is detachably mounted between a fixed clamping member, 30 and an adjustable clamping memberI 3l, carried by the me 25. The member 31! is' adjustable along the bent part of rod 25 to accommodate different sizes of-flasks and has a spring pressedbolt 32 lfor engaging a recess 33'i'n' the opposed end lof the flask.

u Theflask 4 is in the form of a metal shell having an open end 35 through which the `plastic material is inserted for forming the" i mold. Part of the flask is cut away toform v 38 and 39 arranged so as to ermit the bluntl inserted intov4 f ra seat 36 for a removable section or member 37,which comprises a pair of hinged parts nose of the part 39 to the flask below the top member 41. The rear end ofthe part 38 is formed-to provide an upright flange 42, which forms a'nger grip to facilitate the insertion andremoval of the 'and .it is thenallowed to set.

member 37. Extending into the blunt nose 40, is an aperture 43,"forlreceiving a sprue 44 which'is arranged to support a wax or other fusible atterri (not shown) for forming the matrix I1n the mold. Several apertures may be formed in the nose 40'for receiving a plurality of sprues for the purpose of form' y several matrices A,within the same mold. The

bottom of the removable member 37-is formed toV provide a pattern 45 for molding a cru-y cible'which communicates with the matrix' v through a channel which is formed in the mold by the projecting shank of the sprue 44, as hereinafter described.

In the operation of casting a dental in-y lay, a Wax pattern or impression of the inlay is made and placed on the end of the sprue 44 which is then inserted into the aperture 43. The Vflask is removed from the machine and the section 37 isl placed in the seat 36.

A suitable plaster is then pressed through the open end 35 until the entire flask is filled When the plaster has hardened, the section 37 is removed from the flask, leaving the sprue imbedded in the mold., The sprue is then removed by a pair of pliers andthe mold is heated to melt .the wax pattern which is thereby absorbed b the material of the mold. If desired, t e wax pattern .may be washed out of the matrix b boilin water injected through the charme forme ,by the sprue. The flask is clamped in the machine rotation. b?

and the supporting arm 25 is secured against slot17. `n this position .of the flask, the matrix is slightly higher than the crucible so as to prevent-the molten metal from flowing out throughthe channel formed by the i sprue. The gold or other metal isplaced in the Crucible and heated by a blow-torch or the like. When the metal in the crucible has all'been-melted, therackA bar is raised to its retracted position and the catch 18 is then released.'I The release of the catch permits the rack bar to'move downwardly under the action of its spring, thereby xrotating the gear 11 and shaft 10. When the rack barreaches its lowermost position, the supporting rod 25 continues to rotate by its own momentum and the molten metal is forced outwardly from the Crucible into the matrix A where it hardens into the finished casting.

The arrangement of the flask with respect to the rotatable support permits -the metal to' be acted upon by inertia as well as by centrifugal force. When the supporting member 25 stops rotating, the flask may be. taken out of the machine andthe cast removed by ing. the mold.

Although but one specific embodiment of this invention has been herein shown and described. it will be understood that nubreakmerous details of the construction shownl may be altered or omitted without departingufrom the spirit of this invention as de fined by the following claims.

I claim: Y

1. vA `device of the class'describedcomprising-a flask adapted for support on a cen,-

the catch 18 whichengages 'the y trifugal castingv machine, said flask having..V

a removable section comprising a pair of hinged parts, a pattern integrall formed on said removable section for mol ing a crucible,` and a sprue mounted on one of said,

hinged parts for sup orting a fusible pattern adapted to mol a matrix, said sprue being arranged to mold a channel provid# and a removable sprue mounted on one of said hinged parts for supporting a fusible pttern adapted to mold a matrix, said sprue ing arranged to mold a channel providing communication between the matrix and- Crucible. f,

Signed at Chicago this 27th day of Sept., 1921. Y I

JAMES J1 MOUNT. 

